Refinement of equations describing longitudinal-radial vibrations of a circular cylindrical viscoelastic shell

1990 ◽  
Vol 26 (2) ◽  
pp. 161-168
Author(s):  
I. G. Filippov ◽  
K. Kudainazarov
Keyword(s):  
Viscoelastic Shell ◽  
Radial Vibrations ◽  
Cylindrical Viscoelastic Shell ◽  
Circular Cylindrical Viscoelastic Shell

The Vibrations of an Infinite Orthotropic Layered Cylindrical Viscoelastic Shell in an Acoustic Medium

1976 ◽  
Vol 43 (4) ◽  
pp. 668-670 ◽  
Author(s):  
B. S. Berger
Keyword(s):  
Finite Difference ◽  
Difference Scheme ◽  
Numerical Solution ◽  
Finite Difference Scheme ◽  
Elastic Shell ◽  
Numerical Results ◽  
Acoustic Medium ◽  
Viscoelastic Shell ◽  
Cylindrical Viscoelastic Shell ◽  
Acoustic Fluid

In the following a numerical solution is given for the vibration of an orthotropic layered cylindrical viscoelastic shell in an acoustic medium. The acoustic fluid is modeled through a finite-difference scheme. Numerical results for the elastic shell in an acoustic medium agree with previous solutions.

Longitudinal Impact of a Semi-Infinite, Cylindrical, Viscoelastic Shell

1965 ◽  
Vol 32 (4) ◽  
pp. 813-820 ◽  
Author(s):  
R. B. Testa ◽  
H. H. Bleich
Keyword(s):  
Laplace Transform ◽  
Error Estimates ◽  
Asymptotic Methods ◽  
Elastic Shell ◽  
Longitudinal Impact ◽  
Viscoelastic Shell ◽  
Viscous Effects ◽  
The Laplace Transform ◽  
Oscillatory Character ◽  
Cylindrical Viscoelastic Shell

The response of a semi-infinite, cylindrical, viscoelastic shell to longitudinal impact is studied using the Laplace transform. The evaluation by asymptotic methods for large values of time also gives error estimates defining the range of applicability. It is found that, at sufficiently large distances from the point of impact, the oscillatory character of the response of an elastic shell to longitudinal impact is suppressed by viscous effects, resulting in nearly identical solutions for a viscoelastic shell and for an infinitely thin viscoelastic rod of the same material. In addition, it is shown that the solutions for shell and rod, with limitations, are also nearly identical for smaller values of time, where nonasymptotic solutions for the rod apply.

Effect of magnetic field and non-homogeneity on the radial vibrations in hollow rotating elastic cylinder

Meccanica ◽  
2012 ◽  
Vol 48 (3) ◽  
pp. 555-566 ◽  
Author(s):  
A. M. Abd-Alla ◽  
G. A. Yahya ◽  
S. R. Mahmoud
Keyword(s):  
Magnetic Field ◽  
Elastic Cylinder ◽  
Radial Vibrations

scholarly journals The inflation of viscoelastic balloons and hollow viscera

2018 ◽  
Vol 474 (2218) ◽  
pp. 20180102 ◽  
Author(s):  
Riccardo De Pascalis ◽  
William J. Parnell ◽  
I. David Abrahams ◽  
Tom Shearer ◽  
Donna M. Daly ◽  
...  
Keyword(s):  
Peak Pressure ◽  
Fundamental Problem ◽  
Numerical Technique ◽  
Constitutive Behaviour ◽  
Viscoelastic Shell ◽  
Nonlinear Volterra Integral Equation ◽  
Nonlinear Viscoelastic ◽  
Wide Range ◽  
Nonlinear Elastic ◽  
First Time

For the first time, the problem of the inflation of a nonlinear viscoelastic thick-walled spherical shell is considered. Specifically, the wall has quasilinear viscoelastic constitutive behaviour, which is of fundamental importance in a wide range of applications, particularly in the context of biological systems such as hollow viscera, including the lungs and bladder. Experiments are performed to demonstrate the efficacy of the model in fitting relaxation tests associated with the volumetric inflation of murine bladders . While the associated nonlinear elastic problem of inflation of a balloon has been studied extensively, there is a paucity of studies considering the equivalent nonlinear viscoelastic case. We show that, in contrast to the elastic scenario, the peak pressure associated with the inflation of a neo-Hookean balloon is not independent of the shear modulus of the medium. Moreover, a novel numerical technique is described in order to solve the nonlinear Volterra integral equation in space and time originating from the fundamental problem of inflation and deflation of a thick-walled nonlinear viscoelastic shell under imposed pressure.

Fluid-Hammer Effects on Coiled-Tubing Friction in Extended-Reach Wells

SPE Journal ◽  
2016 ◽  
Vol 22 (01) ◽  
pp. 365-373 ◽  
Author(s):  
Silviu Livescu ◽  
Steven Craig ◽  
Bill Aitken
Keyword(s):  
Friction Force ◽  
Numerical Models ◽  
Laboratory Data ◽  
Friction Reduction ◽  
Friction Modeling ◽  
Radial Vibrations ◽  
Friction Forces ◽  
Planning Stage ◽  
Force Matching ◽  
Coiled Tubing

Summary The lateral reach and residual bottomhole-assembly (BHA) loads in extended-reach wells strongly depend on the coiled-tubing (CT) mechanical friction. Detailed CT-friction modeling becomes crucial in the prejob planning stage to ensure successful job predictability. However, current numerical simulators consider constant coefficients of friction (CoFs) that are determined from similar operations without taking into account the effects of the operational and downhole parameters on the CoF for a specific operation. This study outlines the modeling of CT-friction force, CoF, and axial BHA loads depending on the operational and downhole parameters when a fluid-hammer tool is used. Recent theoretical, laboratory, and field data have established how CoF depends on the downhole parameters (Livescu and Wang 2014; Livescu and Watkins 2014; Livescu et al. 2014a, b; Livescu and Craig 2015). Previously, these effects were not considered in the CT numerical models, leading to significant CoF differences among available commercial simulators. For instance, the default CoFs in the current prejob simulations for cased holes, when no lubricant or friction-reducing tools such as fluid-hammer tools and tractors are used, vary between 0.24 and 0.30 or even higher. This makes it extremely difficult to consistently evaluate and compare the friction-reduction effects of lubricants, fluid-hammer tools, and tractors in extended-reach wells, especially when the field operator may be consulting with several service companies that use different commercial force-modeling software. This study presents the CT-force matching and fundamental physics on the basis of modeled fluid forces, including radial forces, drag forces, and, most importantly, pressure forces on the CT-friction forces caused by fluid-hammer tools. Extending the method of characteristics, regularly used for studying pressure pulses in straight pipes, the perturbations method also accounts for the helical shape of the CT. The new CT fluid-hammer model is validated against laboratory data. This rigorous method for calculating the axial BHA load and reduced CT-friction force caused by radial vibrations can be easily implemented in currently available tubing-force analysis (TFA) software for CT operations. This novel approach, which uses detailed CT mechanical-friction modeling to take into account parameters such as temperature, internal pressure, pumping rate, and others, improves predictions for CT reach in lateral wells. These findings broaden the current industry understanding of the CT mechanical friction modeling in extended-reach wells, and show benefits for the industry when considering variable friction modeling in commercial CT simulators.

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